This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A089019 #16 Mar 07 2020 07:58:35
%S A089019 2,13,14,26,38,49,62,67,79,74,86,103,109,133,122,158,146,181,194,194,
%T A089019 182,182,193,199,259,278,247,266,278,254,266,301,301,314,362,338,379,
%U A089019 373,367,427,458,403,434,458,422,446,433,434,518,511,494,482,487,523
%N A089019 First nontrivial x satisfying x^2 - 3*y^2 = d^2, where d=A072330(n).
%H A089019 Jean-François Alcover, <a href="/A089019/b089019.txt">Table of n, a(n) for n = 1..999</a>
%F A089019 a(n) = A086909(n)/2.
%t A089019 Cases[Import["https://oeis.org/A086909/b086909.txt", "Table"], {_, _}][[All, 2]]/2 (* _Jean-François Alcover_, Mar 07 2020 *)
%Y A089019 For corresponding y see A089020.
%Y A089019 Cf. A072330, A072360, A086909, A089020, A096672, A096673, A096674.
%K A089019 nonn
%O A089019 1,1
%A A089019 _Lekraj Beedassy_, Nov 04 2003
%E A089019 Extended by _Ray Chandler_, Jul 03 2004